1. Purpose and Objectives

This guideline aims to provide information about Q-Fever and how to reduce the risk of UQ staff and students who work with animals from becoming infected with Coxiella burnettii bacterium, resulting in Q-Fever illness.

2. Definitions, Terms, Acronyms

Bacterium - A single cell micro-organism some of which can cause disease.

PPE - Personal protective equipment.

Zoonotic - Pertaining to zoonosis, a disease that normally exists in animals but can be transmitted from animals to humans.

Antigens - Substances that can stimulate the immune system to produce antibodies.

3. Guidelines Scope/Coverage

These guidelines apply to all UQ staff, students, visitors and volunteers who work in agricultural settings and/or interact with or work in close proximity to agricultural livestock or other animals (see sections 4 and 5 for further details).

4. Guidelines Statement

Q-Fever is a zoonotic infection transmitted by the bacterial microorganism Coxiella burnetii, usually via dust and aerosols from infected animals. It is a relatively common but preventable condition which, while rarely fatal, can cause a severe acute illness with complications such as hepatitis and pneumonia. It can also cause damage to heart valves and precipitate chronic fatigue and long-term disability.

The organism can infect both wild and domestic animals and their ticks. Companion animals such as cats and dogs can also become infected.

Persons working with animals such as cattle, sheep, goats and feral animals have the greatest risk of transmission and those most at risk include workers from the meat and livestock industry and sheep shearers. Persons working or living in areas frequented by these animals but not actually working with the animals are at some risk also. Persons dealing with animal products in the research setting can also be at risk.

Q-Fever is primarily an occupational disease of workers from the livestock and meat industry. Over 90% of cases of acute Q-Fever occur in new entrants to the workforce or those who have been in the workforce 5 years or less. Q-Fever affects mainly men between 20 and 50. Women entering high-risk occupations should be vaccinated before considering a pregnancy to avoid the significant risk to the foetus in the event of Q-Fever infection occurring in pregnancy.

At The University of Queensland workers considered to be at significant risk of infection transmission include agricultural and farm workers and students, veterinarians and veterinary students and agricultural and wildlife research workers and students.

5. Animals Infected

Coxiella burnetii infects both wild and domestic animals and their ticks, sometimes without any apparent signs of infection. Cattle, sheep and goats are the main reservoirs of human infection, although bandicoots, kangaroos, wallabies, birds, rodents, lagomorphs (hares, rabbits, and pikas), cats and dogs also can be infected. Infected animals shed Coxiella burnetii in their urine, faeces, milk and in particularly high numbers in birth products.

6. Modes of Transmission of Coxiella Burnetii

Coxiella burnetii is a highly infectious bacterium that can survive in harsh environmental conditions. For example, it has survived for 7 to 9 months on wool at 15 to 20°C, for more than 1 month on fresh meat in cold storage and for more than 40 months in skim milk at 4 to 6°C. It is transmitted to humans via inhalation, ingestion, inoculation or via direct contact with infected aerosols or dust.

6.1 Inhalation of aerosols and dust

The predominant mode of infection of humans is via the respiratory tract after inhalation of airborne dust or droplets containing the coxiella. Large numbers of Coxiella burnetii are released in the blood, urine, faeces, milk, birth fluids and placenta of infected animals. Infected aerosols from these products may be released into the environment and consequently infect humans via the respiratory tract. Infected aerosols are released during the slaughter of infected animals or for example during incorrect handling of the above animal products in the research environment.

Coxiella burnetii can survive in dust formed from contaminated birth fluids, blood, faeces or urine. When infected fluids dry out, the bacterium can survive in the dust for many years. Infected dust may settle on the ground, on wool, hides, clothing, straw etc and be disturbed by movement or wind. Contaminated dust can be carried outside the working environment on work clothing, hair, straw, and other formites or on working dogs.

6.2 Ingestion

Consumption of unpasteurised infected milk or milk products such as unripened cheese can lead to infection but is considered to have a lower risk of transmission compared to airborne exposure.

6.3 Inoculation

Infection can occur through subcutaneous inoculation such as being bitten by infected ticks or via a needlestick injury when working with laboratory animals. Human to human transmission is rare but has been known to occur via blood transfusion from blood collected in the late incubation period of primary infection.

6.4 Direct contact

Infection can occur through direct contact with infected material or dust via the conjunctiva and other mucous membranes.

7. Risk Management

A risk assessment should be undertaken in workplaces where agricultural or feral animals are handled or are housed in close proximity to work areas. The following factors should be considered as part of a risk assessment.

Is it likely the worker may inhale aerosols of urine, faeces, milk, birth fluids, placenta, blood and possibly semen from animal sources?

Is it likely the worker may get eye contamination by splashes or aerosols of the substances described above?

Is the worker potentially liable to inhale dust that contains dried body fluids from animals?

If yes, to any of the above, is this exposure very occasional or on a regular basis?

If workers are significantly exposed to the risk of Coxiella burnetii on a regular basis then the following control measures should be instituted:

Visitors who are not immune to Q-Fever and are entering areas considered to harbour a risk for Q-Fever transmission must wear a P2 mask during the period they are present in that workplace.

8. Signs and Symptoms

Symptoms can range from some infected people experiencing no symptoms to those who feel mildly unwell for a few days. Most people however experience severe flu-like symptoms with fever, sweating, nausea, vomiting and diarrhoea for up to 10 days. Some people may experience post Q-Fever Fatigue Syndrome resulting in a prolonged form of the illness with symptoms of tiredness, muscle weakness, headaches and depression continuing for years after the initial infection. Some people with heart problems can experience a severe illness due to complications caused by the heart valves becoming infected.

9. Immunisation Recommendations

Q-Fever vaccine is recommended for University of Queensland workers, students and volunteers who are at risk from exposure to Q-Fever infection and are shown to be susceptible to Coxiella burnetii. This includes personnel who are required to work at or regularly visit abattoirs, farms, stockyards, shearing paddocks and other areas which may expose them to cattle, camels, sheep, goats and kangaroos or their products (including products of conception). Q-Fever vaccine is also recommended for veterinarians, veterinary nurses, veterinary students, agricultural staff and students working with high-risk animals and laboratory personnel handling veterinary specimens or working with the Coxiella burnetii organism.

Workers exclusively working with pigs or at pig abattoirs do not require Q-Fever vaccination.

10. Pre-vaccination Screening

Screening prior to vaccination is undertaken to exclude persons who are already sensitised to Q-Fever antigens and who may therefore experience a severe hypersensitivity reaction if vaccinated. Pre-vaccination screening incorporates taking a detailed history to exclude the likelihood of the person previously having a had Q-Fever infection or being previously vaccinated with Q-Fever vaccine. For those persons without evidence of prior infection or vaccination, further screening tests are undertaken such as a skin-prick test and a blood test to detect immunological evidence of previous Q-Fever infection.

11. Q-Fever Register

The Australian Q-Fever Register is a database that stores information about the immune status of people who have undertaken Q-Fever screening and who consent to being listed on the register. It allows those who may have forgotten or lost their Q-Fever screening or immunisation details to quickly recover this information. Those listed on the register can be safely employed in a new job where there is a risk of contracting Q-Fever without having to re-test. Being on the register can also help avoid the risk of adverse reactions occurring when a person who is already immune to Q-Fever is inadvertently re-vaccinated. Information on the Q-Fever register can only be entered with the consent of the immunised person. For more information about how to join the Q-Fever register please refer to the Australian Q-Fever Register Website.